Clutch Master Cylinders

What is a clutch master cylinder?

A clutch master cylinder is part of the hydraulic system that operates the clutch on a vehicle with manual transmission. The clutch master cylinder is compressed and released by the action of the clutch pedal being operated. The compression of the clutch master cylinder forces hydraulic fluid to the clutch slave cylinder or concentric slave cylinder (CSC) which operates as a result. The operation of the slave cylinder or CSC serves to put pressure on the clutch plate which releases or engages the clutch system that provides drive to the transmission.

How do I choose the correct clutch master cylinder?

There can be different clutch master cylinders listed for the same model of vehicle depending on the exact functions and features that it has.

These may include:

• Number of gears (i.e. 5 speed or 6 speed etc)

• Manual or semi automatic transmission

• Stop start feature

• Cruise control

• Piston bore diameter measurement

• Right or left hand drive

• Transmission type / transmission code

• Vehicle manufacture date (this is not the date the vehicle was registered but the date it was made

• Engine number sequence (up to or after as specific number/letter

• VIN (chassis number) sequence (up to or after as specific number/letter

What brand of clutch master cylinder should I choose?

The technical nature of clutch master cylinders and the fact they are not prone to failure or require servicing means there are not many aftermarket makers of them. This makes the availability of the correct part more difficult. Choosing a brand is not often even a consideration. It is often a case of the correct part being available for your vehicle. If there is a choice of brands for your vehicle we’d advise choosing a part with a long warranty and that is within your budget.

How can I tell my clutch master cylinder needs replacing?

If you are not sure if there are issues with your clutch system we would always recommend that you have your vehicle inspected by a qualified mechanic to receive an accurate diagnosis.

Some of the symptoms of a failing clutch master cylinder are:

• Grinding sound or crunch feeling when changing gear

• The clutch pedal stays pressed to the floor

• Low transmission fluid level or transmission fluid is leaking

• Clutch pedal feels spongy or different to usual